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Snowflake: Support CREATE VIEW myview IF NOT EXISTS #1961

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Merged
merged 3 commits into from
Jul 30, 2025
Merged

Snowflake: Support CREATE VIEW myview IF NOT EXISTS #1961

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26f2680
SGA-11419 Added snowflake ability for if not exists after create view…
etgarperets Jul 21, 2025
46ce27f
SGA-11419 Skipping dialect methods and adding a comment on name if no…
etgarperets Jul 27, 2025
ce9864d
SGA-11419 improved comments, replaced if else flow, added assert to test
etgarperets Jul 29, 2025
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16 changes: 13 additions & 3 deletions src/ast/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3263,6 +3263,8 @@ pub enum Statement {
materialized: bool,
/// View name
name: ObjectName,
// Name IF NOT EXIST instead of IF NOT EXIST name
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Suggested change
// Name IF NOT EXIST instead of IF NOT EXIST name
/// If `if_not_exists` is true, this flag is set to true if the view name comes before the `IF NOT EXISTS` clause.
/// Example:
/// ```sql
/// CREATE VIEW myview IF NOT EXISTS AS SELECT 1`
/// ```
/// Otherwise, the flag is set to false if the view name comes after the clause
/// Example:
/// ```sql
/// CREATE VIEW IF NOT EXISTS myview AS SELECT 1`
/// ```

we could say something descriptive like this?

name_before_not_exists: bool,
columns: Vec<ViewColumnDef>,
query: Box<Query>,
options: CreateTableOptions,
Expand Down Expand Up @@ -4987,6 +4989,7 @@ impl fmt::Display for Statement {
temporary,
to,
params,
name_before_not_exists,
} => {
write!(
f,
Expand All @@ -4999,11 +5002,18 @@ impl fmt::Display for Statement {
}
write!(
f,
"{materialized}{temporary}VIEW {if_not_exists}{name}{to}",
"{materialized}{temporary}VIEW {if_not_and_name}{to}",
if_not_and_name = if *if_not_exists {
if *name_before_not_exists {
format!("{name} IF NOT EXISTS")
} else {
format!("IF NOT EXISTS {name}")
}
} else {
format!("{name}")
},
materialized = if *materialized { "MATERIALIZED " } else { "" },
name = name,
temporary = if *temporary { "TEMPORARY " } else { "" },
if_not_exists = if *if_not_exists { "IF NOT EXISTS " } else { "" },
to = to
.as_ref()
.map(|to| format!(" TO {to}"))
Expand Down
1 change: 1 addition & 0 deletions src/ast/spans.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -400,6 +400,7 @@ impl Spanned for Statement {
if_not_exists: _,
temporary: _,
to,
name_before_not_exists: _,
params: _,
} => union_spans(
core::iter::once(name.span())
Expand Down
22 changes: 18 additions & 4 deletions src/parser/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -5768,12 +5768,25 @@ impl<'a> Parser<'a> {
) -> Result<Statement, ParserError> {
let materialized = self.parse_keyword(Keyword::MATERIALIZED);
self.expect_keyword_is(Keyword::VIEW)?;
let if_not_exists = dialect_of!(self is BigQueryDialect|SQLiteDialect|GenericDialect)
&& self.parse_keywords(&[Keyword::IF, Keyword::NOT, Keyword::EXISTS]);
let allow_unquoted_hyphen = dialect_of!(self is BigQueryDialect);
let mut if_not_exists = false;
let name: ObjectName;
let mut name_before_not_exists = false;
if self.peek_keywords(&[Keyword::IF, Keyword::NOT, Keyword::EXISTS]) {
// Possible syntax -> ... IF NOT EXISTS <name>
if_not_exists = self.parse_keywords(&[Keyword::IF, Keyword::NOT, Keyword::EXISTS]);
name = self.parse_object_name(allow_unquoted_hyphen)?;
} else {
// Possible syntax -> ... <name> IF NOT EXISTS
// Supported by snowflake but is undocumented
name = self.parse_object_name(allow_unquoted_hyphen)?;
if self.parse_keywords(&[Keyword::IF, Keyword::NOT, Keyword::EXISTS]) {
if_not_exists = true;
name_before_not_exists = true;
}
}
// Many dialects support `OR ALTER` right after `CREATE`, but we don't (yet).
// ANSI SQL and Postgres support RECURSIVE here, but we don't support it either.
let allow_unquoted_hyphen = dialect_of!(self is BigQueryDialect);
let name = self.parse_object_name(allow_unquoted_hyphen)?;
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Would it work to only put something like this line after we've parsed? name

let name_before_not_exists = !if_not_exists && self.parse_keywords(&[Keyword::IF, Keyword::NOT, Keyword::EXISTS]);
let if_not_exists = if_not_exists || name_before_not_exists;

thinking if so that would let us avoid the if/else and mut

let columns = self.parse_view_columns()?;
let mut options = CreateTableOptions::None;
let with_options = self.parse_options(Keyword::WITH)?;
Expand Down Expand Up @@ -5840,6 +5853,7 @@ impl<'a> Parser<'a> {
temporary,
to,
params: create_view_params,
name_before_not_exists,
})
}

Expand Down
15 changes: 15 additions & 0 deletions tests/sqlparser_common.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -8040,6 +8040,7 @@ fn parse_create_view() {
temporary,
to,
params,
name_before_not_exists: _,
} => {
assert_eq!(or_alter, false);
assert_eq!("myschema.myview", name.to_string());
Expand Down Expand Up @@ -8108,6 +8109,7 @@ fn parse_create_view_with_columns() {
temporary,
to,
params,
name_before_not_exists: _,
} => {
assert_eq!(or_alter, false);
assert_eq!("v", name.to_string());
Expand Down Expand Up @@ -8157,6 +8159,7 @@ fn parse_create_view_temporary() {
temporary,
to,
params,
name_before_not_exists: _,
} => {
assert_eq!(or_alter, false);
assert_eq!("myschema.myview", name.to_string());
Expand Down Expand Up @@ -8196,6 +8199,7 @@ fn parse_create_or_replace_view() {
temporary,
to,
params,
name_before_not_exists: _,
} => {
assert_eq!(or_alter, false);
assert_eq!("v", name.to_string());
Expand Down Expand Up @@ -8239,6 +8243,7 @@ fn parse_create_or_replace_materialized_view() {
temporary,
to,
params,
name_before_not_exists: _,
} => {
assert_eq!(or_alter, false);
assert_eq!("v", name.to_string());
Expand Down Expand Up @@ -8278,6 +8283,7 @@ fn parse_create_materialized_view() {
temporary,
to,
params,
name_before_not_exists: _,
} => {
assert_eq!(or_alter, false);
assert_eq!("myschema.myview", name.to_string());
Expand Down Expand Up @@ -8317,6 +8323,7 @@ fn parse_create_materialized_view_with_cluster_by() {
temporary,
to,
params,
name_before_not_exists: _,
} => {
assert_eq!(or_alter, false);
assert_eq!("myschema.myview", name.to_string());
Expand Down Expand Up @@ -16377,3 +16384,11 @@ fn parse_drop_stream() {
}
verified_stmt("DROP STREAM IF EXISTS s1");
}

#[test]
fn parse_create_view_if_not_exists() {
let sql: &'static str = "CREATE VIEW IF NOT EXISTS v AS SELECT 1";
let _ = all_dialects().verified_stmt(sql);
let sql = "CREATE VIEW v IF NOT EXISTS AS SELECT 1";
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From a quick look I couldn't find which dialects in practice support this syntax? Do you have a link to documentation for one such dialect?

related the MR not super sure it would be necessary to have this behavior covered by a flag and the parser can always look to accept CREATE VIEW IF NOT EXISTS v, as well as the other syntax if its relevant)

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You're right, I couldn't find official documentation for this syntax, though we have confirmed it works in practice on Snowflake.

I'm happy to remove the dialect flag and update the parser to support both forms for all dialects. Let me know if you'd like me to proceed with that change.

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Ah yeah in that case I think we can remove the dialect flags, not sure that we need to support both forms if CREATE VIEW v IF NOT EXISTS is not supported by any dialect

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It's supported in snowflake, but not officially documented.

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Ah alright, in that case yeah I think we could skip the dialect methods entirely and let the parser accept either format if they show up? Also we can add a comment flagging that the second format is supported by snowflake but is undocumented

let _ = all_dialects().verified_stmt(sql);
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Can we add a test case for CREATE VIEW IF NOT EXISTS AS SELECT 1 to verify how the parser behaves in that scenario?

}
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